Nuclear Single Passenger Earth SSTO

[sevenperforce]

23 minutes ago, Spacescifi said:

The calculations are off... at least as far as I am concerned for the OP.

It is not a methnuclear rocket.

It is a methnuclear AIR BREATHING rocket.

@kerbiloid and I were discussing the pure-rocket mode. 

That being said, a hydrogen airbreather has a much higher specific impulse and usable thrust range than a methane airbreather. Whether you're actually combusting your airflow or simply using it as added reaction mass, you want your exhaust velocity to be at max. A NERVA-type NTR pushing methane would be able to generate net-positive thrust in its airbreathing mode up to 4.6 km/s; if it is pushing liquid hydrogen it would be able to generate net-positive thrust in the airbreathing mode beyond orbital velocity.

If you're landing, that is less important and you do want more thrust, which methane will certainly give you.

[Spacescifi]

1 hour ago, sevenperforce said:

@kerbiloid and I were discussing the pure-rocket mode. 

That being said, a hydrogen airbreather has a much higher specific impulse and usable thrust range than a methane airbreather. Whether you're actually combusting your airflow or simply using it as added reaction mass, you want your exhaust velocity to be at max. A NERVA-type NTR pushing methane would be able to generate net-positive thrust in its airbreathing mode up to 4.6 km/s; if it is pushing liquid hydrogen it would be able to generate net-positive thrust in the airbreathing mode beyond orbital velocity.

If you're landing, that is less important and you do want more thrust, which methane will certainly give you.

 

Pure rockets, awesome though they are just a stepping stone.

The true SSTO's of the future will be NTTR ideas like John Bucknell's and variations of that.

It seems a combined propellant approach is required for an NTTR SSTO.

Namely methane tank with air breathing NTTR for landing or faster flight.

Just airbreathing NTTR if trying to save methane.

Hydrogen tank with whatever air one can snatch along the way to orbit speed.

 

Result IRL.

You really don't want large forward profile for launch.

 

For IRL I would add inflatable rooms to come out the hull for living space while in space. Rather than using more hull

Edited March 12, 2020 by Spacescifi

[sevenperforce]

2 hours ago, Spacescifi said:

Pure rockets, awesome though they are just a stepping stone.

The true SSTO's of the future will be NTTR ideas like John Bucknell's and variations of that.

Re-entry is the problem.

2 hours ago, Spacescifi said:

It seems a combined propellant approach is required for an NTTR SSTO.

For the record, I agree.

[Spacescifi]

1 hour ago, sevenperforce said:

Re-entry is the problem.

For the record, I agree.

 

Yes IRL. In scifi, especially media scifi, it hardly ever is.

IRL the only solution I could think of is some kind of magnetic field bow shock. Maybe deflect the air plasma somehow?

The other solution is heat resistant inflatable water balloons to absorb the oncoming heat while steaming away. Problem is that most of the payload won't be water, and water is used and needed for so many other things.

 

 

[sh1pman]

33 minutes ago, Spacescifi said:

IRL the only solution I could think of is some kind of magnetic field bow shock. Maybe deflect the air plasma somehow?

 

There is a potential solution, and it is almost exactly what you described:

 

[Spacescifi]

13 minutes ago, sh1pman said:

There is a potential solution, and it is almost exactly what you described:

 

 

Nice.

 

So it is like I thought... we humans can play like we are Captain Kirk, we can even play like we are God. Yet the universe offers certain parameters and limits, but within those... we can do just about anything we set our minds to do or dream up.

How long it lasts or exists is difficult to predict... but we sure can build or do anything as a species.

[sevenperforce]

15 hours ago, sh1pman said:

There is a potential solution, and it is almost exactly what you described:

 

The magnetoshell aerocapture design is only good for capture from hyperbolic trajectories, not for proper re-entry.